1. Field of the Invention
The present invention relates generally to a karaoke system for a pre-recorded musical accompaniment for singing. More specifically, the invention relates to a karaoke system which can reproduce a pre-recorded musical accompaniment through a speaker, and, in conjunction therewith, can display lyric words and a background video image corresponding to a mood of the music to be sung in synchronism with progress of the music.
2. Description of the Related Art
[Primary Technology Immediately Before Appearance of Communication Karaoke]
Karaoke system can be classified into a several kinds depending upon types of contents (software of karaoke). One of typical karaoke system is a type called a Laser Karaoke (tradename). In this type of apparatus, the contents are prepared and recorded in a recording medium in the following manner.
A musical accompaniment for singing is actually played and recorded (an audio signal is recorded). On the other hand, video image suited with a mood of the music is actually filmed and edited. The video image thus prepared will be hereinafter referred to as "background video image". Lyric words of the music to be sung are superimposed on the background video image so as to be advanced in synchronism with progress of the musical accompaniment to be reproduced. Such background vide image together with the lyric words will be hereinafter referred to as "lyric accompanying image".
As a storage medium, an optical analog video disk called as a laser disc (tradename) has been used. On the optical analog video disk, a composite signal, in which an analog audio signal of the musical accompaniment, and an analog vide signal of the lyric accompanying image dedicated for the corresponding musical accompaniment are superimposed with an appropriate modulation, is recorded. Such disk is replicated in large amount for distribution to load on a large number of the karaoke system.
By means of a video disk player in the karaoke system, a predetermined track on the disk containing a music desired to sing is reproduced. Then, the musical accompaniment of the desired music is reproduced through the speaker. At the same time, in synchronism with reproduction of the musical accompaniment, the lyric accompanying image is reproduced on a CRT display.
In another typical karaoke system, a digital storage medium standardized as a video CD (originally, a video CD standard is an advanced type of an initial karaoke CD standard). Production process of the contents is basically the same as those of the foregoing laser karaoke type. Namely, the musical accompaniment is actually played and recorded, and the lyric accompanying image is filmed and edited.
Then, according to a MPEG1 (Moving Picture Experts Group 1) standard, the audio signal of the musical accompaniment is converted by a digital compression coding process, and the video signal of the lyric accompanying image is converted by digital compression coding process for recording on the video CD in multiplexed manner. Such disk is replicated in large amount for distribution to load on a large number of the karaoke systems.
By means of a CD-ROM player in the karaoke system, a predetermined track on the disk containing a music desired to sing is reproduced. Then, the musical accompaniment of the desired music is reproduced through the speaker. At the same time, in synchronism with reproduction of the musical accompaniment, the lyric accompanying image is reproduced on a CRT display.
[Communication Karaoke]
A communication karaoke is a recent primary system. The communication karaoke system is significantly different from the foregoing two types in a mechanism for generating the musical accompaniment. Musical software for a typical communication karaoke system is produced by a technology of MIDI (Music Instrument Digital Interface) instrument or DTM (Desktop Music) by a personal computer, and express music in a data format according to the MIDI standard. As is well known, the MIDI data is not the digitized audio signal but a control data sequence for generating an audio signal of the music by controlling a synthesizer in time series.
Comparing the digital audio data (hereinafter referred to as "DA data") generated by digital compression coding of the musical accompaniment recorded by orchestration of instruments and the MIDI data generating the same musical accompaniment by the synthesizer simulating substantially the same orchestration of the instruments, the MIDI data has much smaller data amount than the digital audio data. However, it is difficult to synthesize a human voice chorus with realistic feeding by the synthesizer. Therefore, in many cases, a PCM data generated by digital recording a human voice chorus is accompanied with the MIDI data of the musical accompaniment. Even in total of the MIDI data and the PCM data, the data amount is much smaller than the digital compression coded digital audio data.
On the other hand, expression of the musical accompaniment primarily based on the MIDI data including mechanism for partially adding the digital recorded data (PCM data) such as the human voice chorus and so forth will be hereinafter referred to as a karaoke generation data. To this karaoke generation data, the lyric display data is added. The lyric display data is a graphics processing data for displaying the lyric words in superimposing manner. In the lyric display data, expression data, such as a lyric word sequence, a display layout data, display sequence data, singing timing guidance and so forth may be contained.
Since the karaoke generation data can express the karaoke musical accompaniment with quite small data amount (accompanied lyric display data is sufficiently small in the data amount), a compact and inexpensive hard disk drive for a personal computer may be used even for a karaoke database in a scale containing in excess of ten thousands of music. In the same reason what the data amount is satisfactorily small, a communication karaoke system, in which karaoke software (Karaoke generation data and the lyric display data) of new music can be distributed from a host system to karaoke terminal systems spread in wide area through a telephone network.
It should be noted that even in the communication karaoke system, it is typical to use a package medium for karaoke software (Karaoke generation data and the lyric display data) for a huge amount of existing musics. Namely, the CD-ROM recording the karaoke software of the existing music is replicated in large amount for loading in the CD-ROM player upon shifting of the karaoke terminal systems. Therefore, communication system is used as means for supplementing the karaoke software of new music not contained in the disk.
The communication karaoke system is a large scale network, in which huge number of the karaoke terminal systems spread in a wide area throughout the country and a host system managed by a business proprietor are connected through a communication network, and is a multimedia system handling audio information, character image information and/or moving picture image. In addition to the feature that the software of the new music can be supplied quickly, various applied functions utilizing a network resource has been realized. For instance, the business proprietor of the communication karaoke may collect operation record of respective terminal systems through the host system, perform inspection of respective terminal systems, remote control each individual terminal system on the basis of the operation record and content of contract. Thus, useful and high level operation system or maintenance management system directly associated with karaoke business can be realized. Furthermore, various new entertainment service, information service associated with use environment and not directly related to karaoke play, can be thought of to evaluate toward an intelligent entertainment system highly utilizing the network resource.
The karaoke musical accompaniment generated by controlling a synthesizer by the MIDI data is inherently lower in quality and atmosphere as a music and a tone quality in comparison with the reproduced sound of the digital audio data of the musical accompaniment. In certain genre of music and orchestration of the instruments, the difference of the reproduced sound quality becomes critical negative factor to significantly lower evaluation of a singer and/or listener.
On the other hand, it is a great fun for members enjoying karaoke singing, especially for listeners to watch a video image displayed in the background of the lyric words. Enjoying harmony of the content of the music being sung and the content of the displayed video image, is one of significant entertainment factor. In the communication karaoke, background image is selected with appropriately using images in a common image database. Therefore, even when a measure is taken to avoid apparent mismatching of the content of the music and the content of the image, the quality is significantly lowered in comparison with the system using the lyric accompanying image dedicate for the corresponding music.
In the recent years, a technology for redundancy compression of the audio and video data and a digital signal processing technology concerning transmission has been abruptly progressed. Therefore, it is not technically difficult to establish the communication karaoke system, in which the recorded high quality karaoke musical accompaniment and the lyric accompanying image are transmitted in a form of MPEG audio and video data.
However, it requires much higher cost and significant time to record actual play of the karaoke musical accompaniment with a desired orchestration of the instruments in comparison with generation of the karaoke generation data primarily by the MIDI. Recording all of new music created from time to time with actually playing them for recording high quality karaoke musical accompaniment without causing significant delay, is significant burden for the software provider (business proprietor of karaoke).
Greater burden for the software provider is production of the lyric accompanying image dedicated for each music. In the production process, scenario adapted to the content of each music is prepared, and a short silent film is filmed and edited based on the scenario. This is quite significant work. It is not easy to produce the lyric accompanying images dedicated for respective music created in the rate of several tens per month without significant delay. Therefore, it is quite difficult to maintain distribution speed of the new music as in the current communication karaoke.